Suntech Defaulted on its U.S. Debt in March, is Expected to File For Protection Under Chapter 15

China's onetime solar-power giant Suntech Power Holdings Co. plans to file for bankruptcy protection in U.S. court as its leaders negotiate with the holders of more than $500 million in U.S. convertible bonds, according to people familiar with the matter.

Suntech Power Holdings, which was once the world's largest solar panel maker, defaulted on its U.S. debt in March, and financial professionals in the Cayman Islands—where the holding...